Re: pg_dump: largeobject behavior issues (possible bug)

>>>>> "Joshua" == Joshua D Drake <jd(at)commandprompt(dot)com> writes:

Joshua> The database dumps fine as long as we don't dump large
Joshua> objects. However, if we try to dump the large objects, FreeBSD
Joshua> will kill pg_dump as it will consume all free memory and
Joshua> swap. With Andrew's help we were able to determine the
Joshua> following:

Joshua> There is a memory cost of about 160 bytes per largeobject.

I may have the exact number here wrong, it was just a quick eyeball of
the data structures (and depends on malloc overheads anyway).

The relevant code is getBlobs in pg_dump.c, which queries the whole of
pg_largeobject_metadata without using a cursor (so the PGresult is
already huge thanks to having >100 million rows), and then mallocs a
BlobInfo array and populates it from the PGresult, also using pg_strdup
for the oid string, owner name, and ACL if any.

--
Andrew (irc:RhodiumToad)